docs: def tabulate(self):
          """Return a simplified version of the spectrum.
  
          Composite spectrum can be overly complicated when it
          has too many components and sub-components. This method
          copies the following into a simple (tabulated) source spectrum:
  
          * Name
          * Wavelength array and unit
          * Flux array and unit
  
          Returns
          -------
          sp : `ArraySourceSpectrum`
              Tabulated source spectrum.
  
          """
          sp = ArraySourceSpectrum(wave=self.wave,
                                   flux=self.flux,
                                   waveunits=self.waveunits,
                                   fluxunits=self.fluxunits,
                                   name='%s (tabulated)' % self.name)
          return sp